The present invention relates generally to a body support apparatus, that is, an apparatus suitable for supporting at least part of a living human being. In particular the invention relates to a bed, but also has application to chairs and other apparatus for supporting a person, or part of a person (for example, just their legs).
Beds of the prior art commonly comprise a mattress that supports the body, the mattress conforming, at least to a limited extent, to the shape of the person lying on the bed. A purpose of the mattress is to provide comfort by supporting the body, whilst avoiding having parts of the body in contact with the mattress being exposed to points of high pressure. Conventional mattresses have certain disadvantages however.
One such disadvantage is that dust and other matter can accumulate within the mattress thereby providing a suitable environment for dust mites to live in. (There has been evidence to suggest a link between the presence of dust mites within mattresses and the provocation of asthma attacks in those susceptible to such attacks.) Furthermore, conventional mattresses are generally heavy, generally difficult to clean and can be expensive to replace.
There are beds of the prior art such as, for example, water beds that do not require the provision of a conventional mattress, thereby avoiding at least some of the above-mentioned disadvantages associates with such mattresses. Water beds however suffer from other disadvantages. For example, water beds can leak. Also water beds suffer from the undesirable effects of xe2x80x9cballooningxe2x80x9d, that is, when one region of the bed is depressed another region rises owing to the volume of water being substantially constant and xe2x80x9cwave motionxe2x80x9d, where the surface of the bed can continue to move owing to wave-like motion of the water in the bed. Both ballooning and wave motion can reduce the comfort of the user or users of the bed.
Attempts have been made in the prior art to provide a bed which does not require a conventional mattress and which also does not suffer from at least some of the above-mentioned disadvantages associated with water beds. One such attempt is described in U.S. Pat. No. 5,446,933. U.S. Pat. No. 5,446,933 discloses a bed comprising an array of vertically arranged dowels, which are able to move vertically, and which define a body supporting surface. The bottoms of the dowels interact with a flexible fluid chamber and downward pressure exerted on the chamber by any of the dowels is transmitted via the fluid to the other dowels and additionally to a pressure counterbalance that is displaceable by the fluid according to the fluid pressure. The bed of U.S. Pat. No. 5,446,933 whilst reducing the ballooning effect found in water beds still suffers from at least some of the other above-mentioned disadvantages associated with water beds.
It is an object of the present invention to provide a body support apparatus that mitigates at least some of the above-mentioned disadvantages associated with the body support apparatuses of the prior art.
Accordingly, the present invention provides a body support apparatus comprising
a support surface defined by support members, each support member being mounted for movement in a direction substantially normal to the support surface, wherein
at least a multiplicity of the support members are so arranged that movement of any one of those support members in a direction substantially normal to the support surface and beyond a threshold distance relative to an adjacent support member causes movement in substantially the same direction of said adjacent support member, there being substantially no movement of said adjacent support member caused by the movement of said any one of those support members when the distance of relative movement is below the threshold distance and
a plurality of said multiplicity of support members are resiliently urged towards an unloaded position.
The body support apparatus can be used without the provision of a thick mattress and yet without prejudicing comfort, because the support surface defined by the support members conforms substantially to the shape of the body of the user, by means of the combined effects of the resiliently movable support members and the way in which the multiplicity of support members move in relation to each other.
Furthermore the body support apparatus need not rely on water or other fluids to make the apparatus comfortable to use and so the apparatus need not be prone to leaks of such fluids. Also the apparatus can easily be configured so that movement of one support member in one direction does not cause movement of another support member in an opposite direction. Thus the apparatus need not suffer from the affects of xe2x80x9cballooningxe2x80x9d. Moreover, since a support member must move more than a threshold distance in order to cause movement of an adjacent support member xe2x80x9cwave motionxe2x80x9d can be reduced, if not eliminated. Also the apparatus when used as a bed by two people need not suffer from the xe2x80x9croll togetherxe2x80x9d effect (where the weight of one person causes the support surface to incline towards that person to such an extent that the support surface in the region of the second person becomes inclined and urges, by gravity, the second person towards the first person, causing the two people to xe2x80x9croll togetherxe2x80x9d).
It should be understood that where the term xe2x80x9cbody support apparatusxe2x80x9d is used herein with reference to the present invention the term includes within its scope beds, chairs and other apparatus capable of supporting a living human being or an animal having a mass greater than 1 Kg or a part of such a human being or animal.
For the sake of convenience a support member, which is so arranged that movement of it in a direction substantially normal to the support surface and beyond a threshold distance relative to an adjacent support member causes movement in substantially the same direction of said adjacent support member (there being substantially no movement of said adjacent support member caused by the movement of the first mentioned support member when the distance of relative movement is below the threshold distance) shall hereinafter be referred to as an xe2x80x9cactive support memberxe2x80x9d.
Preferably the apparatus comprises more than 250 support members.
The respective threshold distances in relation to pairs of adjacent active support members are conveniently substantially the same. The distance of relative separation between a pair of adjacent active support members may conveniently be limited, in that there may be a maximum distance of separation between adjacent support members during normal use of the apparatus. The maximum distance of separation between a pair of adjacent active support members may be dependent on the threshold distance associated with that pair of support members. When all of the support members in a region are active support members and there is such a maximum distance of relative separation between pairs of adjacent active support members, a maximum angle of inclination of the support surface in that region may be predetermined by selecting appropriate threshold distances.
Preferably the apparatus is so arranged that the angle of inclination of the support surface relative to the support surface when unloaded is limited to a maximum angle.
Preferably that maximum angle is between 5 and 45 degrees and more preferably between 10 and 30 degrees.
Preferably all of the multiplicity of support members are resiliently urged towards an unloaded position. Preferably, each of a plurality of the resiliently urged support members are directly resiliently urged towards an unloaded position, for example, by means of a respective resilient device. Not all of the resiliently urged active support members need to be directly resiliently urged as can be illustrated as follows. Consider an apparatus according to the present invention, including first and second adjacent active support members, only the second of which is directly resiliently urged by, for example, a spring. When the first active support member moves beyond its threshold distance it will cause movement of the second member and will then be subjected to the resilient bias of that second member towards its unloaded position. Preferably, all of the active support members are resiliently urged, either directly or indirectly.
The support members that are directly resiliently urged towards an unloaded position may each be so configured that the return force increases continuously with the distance of the support member from the unloaded position.
Preferably, less than two thirds, for example about a half, of the active support members are directly resiliently urged towards an unloaded position.
Preferably, each of a plurality of the resiliently urged support members are directly resiliently urged towards an unloaded position by a respective spring, advantageously a tension spring. It will be understood that in the present context a xe2x80x9ctension springxe2x80x9d is a spring that is configured to provide a returning force when extended. For example, movement of a support member associated with such a tension spring away from its unloaded position, caused by for example the body of a person exerting a downward force onto the support surface, causes that tension spring to extend thereby providing a force equal and opposite to the downward force on the support member. Whilst compression springs (as commonly used in conventional mattresses) could be used, it has been found that an apparatus using tension springs generates less noise, when the support members move in use, than a similar apparatus using compression springs.
The apparatus is preferably arranged so that each of the resiliently urged support members is prevented from reaching its unloaded position. Each of the resiliently urged support members may therefore always be loaded (subjected to a return force) even when in its rest position (the position at which the support member rests when there are no external loads). For example, each of the resiliently urged support members may be associated with stop means that restricts the movement of the resiliently urged support member. Preferably, each of the resiliently urged support members is associated with a respective stop. The provision of a stop or stop means has several advantages: manufacture of the apparatus may be made easier; the apparatus may be so configured that the support members can not easily be pulled out of the apparatus; and/or the position on each support member of the stops or stop means can be such that the support surface is substantially flat arid level. The stop advantageously comprises a decelerating device. If, in use, a resiliently urged support member has been moved by a relatively large distance and is subjected to a relatively large returning force, and the external force is suddenly removed (for example, a person supported by the apparatus quickly moves) the decelerating device may prevent the support member from continuously accelerating towards its rest position at great speed. If a support member were allowed to return to its rest position without being decelerated and arrived at its rest position at great speed, undesirable noise could be generated and also the user might still be in a position in which they would feel the impact of the returning support member, which would of course be highly undesirable.
Conveniently the decelerating device comprises a spring. Alternatively, the decelerating means may comprise a compressible resilient material such as a foamed plastic or the like. The arrangement of the active support members may also assist in preventing a given individual support member from continuously accelerating towards its rest position, if the apparatus is so arranged that there is a maximum distance of separation between adjacent active support members. For example, if the external load on a first support member is suddenly reduced, it is likely that there will still be a substantial load supported by a second support member near to that first support member (for example, if the apparatus is used as a bed and the user of the bed rolls over, then some or all of the load supported by certain support members will effectively be transferred to other support members nearby).
The second support member would be displaced from its rest position by a distance sufficiently large enough to prevent adjacent support members and the first support member from returning to their respective rest positions by virtue of there being a maximum relative separation distance between adjacent active support members.
Whilst the apparatus may be designed so that it could be used to support a person in comfort directly on the support surface defined by the support members, the apparatus preferably further includes a flexible padded sheet arranged over the support surface. Preferably the sheet is able to be easily removed from the rest of the apparatus. The sheet may then be easily washed and a hygienic and clean surface on which the user can be supported can be maintained in a straightforward and low cost manner. Preferably, the sheet is removably fixed at a plurality of points at the periphery of the support surface. The sheet may then be relatively loosely fixed in position thereby allowing the support members to move freely beneath the sheet.
The construction of the apparatus is advantageously such that there is no requirement for the apparatus to be sealed in any substantial way. The apparatus is advantageously so configured that air is free to pass from immediately beneath the support surface, via the opposite side of the apparatus, to the exterior of the apparatus. Preferably, the apparatus is so configured that air is free to pass from the exterior of, and more preferably from underneath, the apparatus to within the apparatus and then out again via a different route. The user may therefore be cooled by the resulting movement of air which may be especially advantageous if the apparatus is in the form of a bed. Movement of air may be assisted, for example, by means of an air moving device, which can force air through the apparatus and may include air pumps, fans or the like. The temperature of the air passed through the apparatus may be controlled. For example, cool air could be passed through the apparatus to cool the user or alternatively heated air could be passed through the apparatus to warm the user. Since the apparatus, when used as bed, does not require the provision of a thick mattress the air can be passed to a region very close to the user if not directly to the user.
Preferably, the support surface is defined by an array of support members. The ends (that define the support surface) of the support members are preferably so arranged that the space between adjacent support members is relatively small or even negligible. Preferably, pairs of ends of adjacent support members are so configured that one end has a formation that engages with a formation in the other end. Advantageously, the movement of a support member is guided relative to an adjacent support member by means of their respective formations interacting with each other. The formation in a given support member advantageously comprises a recess. The area of possible contact, during normal use, between a pair of adjacent support members can thereby be reduced (in comparison to a similar pair of support members without such formations), whereby friction can be reduced. Preferably each formation is such that at least one side of the end of the support member (a side that contacts an adjacent support member) has two recesses defining a raised portion.
Furthermore, an end of one support member may have a recessed groove running in a direction parallel to the direction in which that support member may be moved and the end of the adjacent support member may have a protrusion that is accommodated by the groove. During manufacture of the apparatus the ends of the support members may thus be connected together in a row before that row is assembled in the rest of the apparatus. Manufacture of the apparatus can thereby be made easier. In use of the fully assembled apparatus the protrusion of one formation is able to move freely along the groove in which it is accommodated.
Preferably, the support surface is defined by rows of support members. The ends of the support members in each row may, in their respective rest positions, be directly adjacent to the ends of the support members in the adjacent row (the ends defining a square grid), but preferably the ends of support members in successive rows are staggered.
Each support member may comprise a rod connected to a cap, the caps being at the ends of the support members that define the support surface. Each cap may be formed integrally with its respective rod or alternatively each cap may be provided separately to the rod and subsequently fixed thereto. Each cap may be fixed to its respective rod by means of a snap-fit fixing. The caps may be formed of a different material to the rods.
The rods may be arranged in a square grid formation and the caps may be arranged in staggered rows by means of caps being positioned off centre in relation to their respective rods. Arranging the support members so that their ends form staggered rows assists in maintaining the positions of the ends of the support member in relation to each other.
The ends of the support members that define the support surface are advantageously rounded. The ends being so rounded make the support surface more comfortable especially when it conforms to the shape of the body of the user. The rounded ends need not be convex in their centres (when viewing end on), but preferably the rounded ends are such that the end face (that region visible when viewing a support member end on) is substantially entirely convex.
Advantageously guide assemblies are provided to guide the movement of the support members in a direction substantially normal to the support surface. One guide assembly may guide a plurality of support members.
Each guide assembly may guide a row of support members. Preferably each guide assembly guides two rows of support members. A guide assembly which guides two rows of support members, advantageously has a cross-section generally in the form of the letter xe2x80x98Txe2x80x99. Each guide assembly may be formed of a light and strong material, for example, aluminium. Each guide assembly may additionally comprise a further material, such as timber, that assists in guiding the support members in a manner that avoids direct contact between the support members and the rest of the guide assembly, whereby the noise generated during use of the apparatus can be reduced. In the case where a guide assembly guides a row of a plurality of support members, the guide assembly is advantageously so configured to reduce sagging of the guide assembly during use. For example, the guide assembly may be curved so that it is slightly raised in the region where the support members in the middle of the row are guided. Alternatively the guide assembly may be pre-stressed so that the guide assembly, in the region where the support members in the middle of the row are guided, resists downwards movement during use.
Advantageously, the guide assembly comprises a relatively rigid bar (for example of aluminium), with for example a T-shaped cross-section, and at least one resilient bar of a relatively resilient, but stiff, material (for example timber) that has, prior to being secured to the rigid bar, a curvature along its length different from that of the rigid bar, preferably so that the middle of the resilient bar is raised above both of its ends. Thus in the assembled apparatus, the resilient bar can be secured to the rigid bar in such a way that the shape of the surface of the resilient bar against the rigid bar conforms substantially to the shape of the corresponding surface of the rigid bar, whereby the resilient bar exerts forces on the rigid bar that oppose the forces exerted on the guide assembly by a body resting on the support surface during use of the apparatus.
Conveniently, when the resiliently urged support members are urged towards an unloaded position by a respective spring, one end of the spring may act on the support member and the other end of the spring may act on the guide assembly. The end of the spring that acts on the guide assembly may be connected to the guide assembly by means of one or more coils of the spring being accommodated in a portion of the guide assembly in such a manner that axial movement of those coils towards the other end of the spring is prevented. Preferably, the spring, during construction of the apparatus, can be inserted into that portion of the guide assembly simply by translational movement in a direction substantially perpendicular to the axis of the spring.
The apparatus preferably further includes a drive device capable of moving one or more support members. Advantageously a multiplicity of the support members are drivable by a drive device. The or each drive device may be arranged to vibrate one or more support members. The support members may be so arranged to produce driven wave like motion. The support members may therefore advantageously be driven, in use, to provide a massaging effect. The apparatus may be so configured that a drive device directly drives only one support member or alternatively one drive device may directly drive several support members. The apparatus may be so configured that one or more regions of the support surface may be drivable independently of the rest of the support surface. The apparatus may be configured that substantially the entire support surface is movable by means of the drive device(s).
The apparatus is preferably so configured that it is able to support a weight of 250 Kg. Advantageously the apparatus is so configured that it is able to support completely an adult human being and preferably two adult human beings. The apparatus may be further provided with acoustic insulation, to reduce the noise produced when the support members move during use.
The present invention further provides a bed incorporating the apparatus described above with reference to the present invention. Advantageously, the bed is so configured that it does not suffer substantially from the roll together effect.
The present invention yet further provides a kit of parts including a plurality of modules,
each module comprising a support surface defined by support members,
each support member being mounted for movement in a direction substantially normal to the support surface, wherein
at least a multiplicity of the support members are so arranged that movement of any one of those support members in a direction substantially normal to the support surface and beyond a threshold distance relative to an adjacent support member causes movement in substantially the same direction of said adjacent support member, there being substantially no movement of said adjacent support member caused by the movement of said any one of those support members when the distance of relative movement is below the threshold distance and
a plurality of said multiplicity of support members are resiliently urged towards an unloaded position, the modules being so configured that they may be fixed together to form an apparatus or a bed as described above with reference to the present invention. Accordingly the apparatus/bed may be manufactured in modules, which may then be sold to the consumer, the consumer being able easily to transport and assemble the apparatus/bed for use. Preferably, the modules are so configured that the apparatus/bed is formed by fixing the modules together in a single row. The width of the assembled apparatus/bed thus depends on the width of the modules whereas the length of the assembled apparatus/bed can be adjusted by adding or removing modules. The manufacturer of the modules need only make modules in a small number of standard widths, so that the consumer can purchase a number of modules, each of a width corresponding to the desired width of the apparatus/bed, the number of modules being chosen by the consumer according to the desired length of the assembled aparatus/bed.